The present invention relates to a heat pump type airconditioner which heats a refrigerant with a heat source other than the atmospheric air.
Heretofore, heating apparatuses based on the heat pump cycle have been proposed. Since, however, they employ the atmospheric air as the heat source for the heat pump, a sufficient quantity of heat is not obtained when the temperature of the open air falls in winter or in a cold district. Accordingly, they have the disadvantages that the warming capability is reduced and that the rise to meet the temperature of a warming load is inferior. Further, if the temperature of the refrigerant flowing into the heat-source-side heat exchanger is lowered to increase the quantity of heat which can be absorbed from the atmospheric air, there is the disadvantage that the heat exchanger frosts over, so the heat exchange capability decreases. As an expedient for compensating for the insufficient capability of the heat pump cycle, there is a method in which an electric heater is provided as an auxiliary heat source and disposed in the vicinity of a heat exchanger functioning as a condenser in a warming operation. Such airconditioners, however, have the disadvantages:
(a) that since the capacity of the heater is small relative to the warming load, the heater is sometimes insufficient for the auxiliary heating during warming and has a limited range of use,
(b) that the heater costs more to operate as compared with other heat sources and places many limitations on the airconditioner, such as the requirement for installation of a power supply for the heater, etc.
In order to eliminate the disadvantages of the prior art devices described above, an airconditioner has been proposed in U.S. patent application Ser. No. 362,838 by Nomaguchi et al, assigned to Mitsubishi Denki Kabushiki-Kaisha (corresponding to Japanese Patent Application No. 55-137408). The present invention relates in improvements made from a viewpoint different from that of the aforementioned pending application.